若α,β均为锐角,且满足sina=4*(根号3)/7,cos(α+β)=—11/14,求cosβ=?

问题描述:

若α,β均为锐角,且满足sina=4*(根号3)/7,cos(α+β)=—11/14,求cosβ=?

用a,b代替α,β
a,b是锐角,0